It is known that numerous operational stages are necessary, in the technique referred to above, to go from the thin heat-shrinkable plastic (for example polyvinyl chloride) sheet in the shape of a flat sheath or a continuous sheath, to the container provided with its covering which is, generally decorated.
Various machines have been described to automate these stages, as for example the machine which is the object of the European patent published under the No. 0,000,851 (application No. 78,400,045.7) corresponding to Fresnel U.S. Pat. No. 4,179,863 According to a particularly advantageous embodiment, the machine for fitting sleeves from a continuous thermoplastic sheath consists of a vertical unit with a floating mandrel provided with a narrowing or neck on its length where it is held by the cooperation of rollers and support wheels continuously to assure the following operations: widening of the flat continuous sheath coming from a supply on rollers, introduction onto the mandrel, downward transfer of the shaped sheath, cutting of the latter into lengths of sheath or sleeves of predetermined adequate length, depositing of the sleeves around containers to be covered and/or decorated (French patent application No. 80 20 301 of Sept. 22, 1980).
This unit with a floating mandrel is satisfactory and makes possible very high rates of fitting sleeves. However the reliability of a perfect transfer of the sheath (before cutting) onto the container is not total in a certain number of cases. For example, the container can be imperfectly centered under the mandrel. On the other hand, problems arise when the shape of the container is such that the distance between the base of the mandrel and the top of the body of the container is rather large (for example, a bottle with a neck); or again when the diameter of the container is greatest at the top (for example, the crimping of a can), which necessitates a maximum opening of the length of sheath when fitting and then causes difficulties for adjusting this length around the container with a slightly small diameter.